Loss of nitrogen from decomposing nodules and roots of the tropical legume Centrosema pubescens to soil

Samples (20 g) of an air-dry, sieved (<2mm) silty loam with or without (controls) the incorporation of 200 mg root portions of Centrosema pubescens, were moistened to 50% moisture holding capacity at 0.33 bar (33 kPa). The root portions were healthy, freshly harvested, clean samples of nodules, l...

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Main Authors: Chulan, Azizah, Waid, John S.
Format: Conference or Workshop Item
Language:English
Published: Australian Academy of Science 1981
Online Access:http://psasir.upm.edu.my/id/eprint/33883/1/33883%20loss%20of%20nitrogen.pdf
http://psasir.upm.edu.my/id/eprint/33883/
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spelling my.upm.eprints.338832015-04-14T02:49:39Z http://psasir.upm.edu.my/id/eprint/33883/ Loss of nitrogen from decomposing nodules and roots of the tropical legume Centrosema pubescens to soil Chulan, Azizah Waid, John S. Samples (20 g) of an air-dry, sieved (<2mm) silty loam with or without (controls) the incorporation of 200 mg root portions of Centrosema pubescens, were moistened to 50% moisture holding capacity at 0.33 bar (33 kPa). The root portions were healthy, freshly harvested, clean samples of nodules, laterals or radicles; treatments Nod, Lat and Rad respectively. Soil samples were incubated aerobically at 30 C for 16 weeks. The radicles, laterals and nodules respectively contained 1.65, 3.46 and 6.91 mg N per sample and their C to N ratios were 16.5, 7.0 and 4.2. The root fragments disappeared rapidly and less than 40% and 10% of their initial dry weight remained after 1 and 16 weeks respectively; nodules decomposed more rapidly than laterals and laterals more quickly than radicles. At 16 weeks the total N contents of the controls had not changed but Rad, Lat and Nod soils respectively showed gains over the controls from week 1 onwards and by week 16, these amounted to 8.2, 17.1 and 31.8%. Concentrations of mineral N increased in all soils from week 4 onwards and by week 16, the amounts of mineral N that had accumulated in Nod, Lat and Rad were 1.62, 1.16 and 1.14 times greater than in the controls (201 ~ N g-l oven-dry soil). Under the conditions of this experiment, the legume root and nodule tissues discomposed rapidly and all of the legume root N (except an unaccounted for 5.6% of the nodule N) was transferred to the soil without any apparent net loss or gain of volatile N. Australian Academy of Science 1981 Conference or Workshop Item PeerReviewed application/pdf en http://psasir.upm.edu.my/id/eprint/33883/1/33883%20loss%20of%20nitrogen.pdf Chulan, Azizah and Waid, John S. (1981) Loss of nitrogen from decomposing nodules and roots of the tropical legume Centrosema pubescens to soil. In: Nitrogen Cycling in South-East Asian Wet Monsoonal Ecosystems, 5-10 Nov. 1979, Chiang Mai University, Thailand. (pp. 150-153).
institution Universiti Putra Malaysia
building UPM Library
collection Institutional Repository
continent Asia
country Malaysia
content_provider Universiti Putra Malaysia
content_source UPM Institutional Repository
url_provider http://psasir.upm.edu.my/
language English
description Samples (20 g) of an air-dry, sieved (<2mm) silty loam with or without (controls) the incorporation of 200 mg root portions of Centrosema pubescens, were moistened to 50% moisture holding capacity at 0.33 bar (33 kPa). The root portions were healthy, freshly harvested, clean samples of nodules, laterals or radicles; treatments Nod, Lat and Rad respectively. Soil samples were incubated aerobically at 30 C for 16 weeks. The radicles, laterals and nodules respectively contained 1.65, 3.46 and 6.91 mg N per sample and their C to N ratios were 16.5, 7.0 and 4.2. The root fragments disappeared rapidly and less than 40% and 10% of their initial dry weight remained after 1 and 16 weeks respectively; nodules decomposed more rapidly than laterals and laterals more quickly than radicles. At 16 weeks the total N contents of the controls had not changed but Rad, Lat and Nod soils respectively showed gains over the controls from week 1 onwards and by week 16, these amounted to 8.2, 17.1 and 31.8%. Concentrations of mineral N increased in all soils from week 4 onwards and by week 16, the amounts of mineral N that had accumulated in Nod, Lat and Rad were 1.62, 1.16 and 1.14 times greater than in the controls (201 ~ N g-l oven-dry soil). Under the conditions of this experiment, the legume root and nodule tissues discomposed rapidly and all of the legume root N (except an unaccounted for 5.6% of the nodule N) was transferred to the soil without any apparent net loss or gain of volatile N.
format Conference or Workshop Item
author Chulan, Azizah
Waid, John S.
spellingShingle Chulan, Azizah
Waid, John S.
Loss of nitrogen from decomposing nodules and roots of the tropical legume Centrosema pubescens to soil
author_facet Chulan, Azizah
Waid, John S.
author_sort Chulan, Azizah
title Loss of nitrogen from decomposing nodules and roots of the tropical legume Centrosema pubescens to soil
title_short Loss of nitrogen from decomposing nodules and roots of the tropical legume Centrosema pubescens to soil
title_full Loss of nitrogen from decomposing nodules and roots of the tropical legume Centrosema pubescens to soil
title_fullStr Loss of nitrogen from decomposing nodules and roots of the tropical legume Centrosema pubescens to soil
title_full_unstemmed Loss of nitrogen from decomposing nodules and roots of the tropical legume Centrosema pubescens to soil
title_sort loss of nitrogen from decomposing nodules and roots of the tropical legume centrosema pubescens to soil
publisher Australian Academy of Science
publishDate 1981
url http://psasir.upm.edu.my/id/eprint/33883/1/33883%20loss%20of%20nitrogen.pdf
http://psasir.upm.edu.my/id/eprint/33883/
_version_ 1643830997674885120
score 13.18916